[InstCombine] allow vector constants for cast+icmp fold

This is step 1 of unknown towards fixing PR28001:
https://llvm.org/bugs/show_bug.cgi?id=28001

llvm-svn: 271810
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 0f119bf..e7f87d4 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -2439,7 +2439,7 @@
   }
 
   // If we aren't dealing with a constant on the RHS, exit early.
-  auto *CI = dyn_cast<ConstantInt>(ICI.getOperand(1));
+  auto *CI = dyn_cast<Constant>(ICI.getOperand(1));
   if (!CI)
     return nullptr;